The practiceEspecially at this time of year, make sure you get exposed to plenty of natural light--either by getting outside every day for a good 45 minutes, or by using a full-spectrum light lamp.
Full-spectrum light lamps can be had for under $100, and unlike drugs, there are no adverse side-effects from using light to boost your mood.
The theory
Some people suffer from SAD (Seasonal Affective Disorder). As we go into winter and daylight hours decrease, they feel depressed and crabby. The solution is more light.
If you work in a windowless office, it's even more important to get light. In Sweden and other Nordic countries, most offices and homes have natural light bulbs, because people there are equipped to deal with long hours of darkness.
(The other solution is to take a mid-winter vacation somewhere sunny. Ten days of bright sunlight in December seems to reset the brain enough to get you through to spring.)
The result
More light works. Within a week of using a light lamp, people affected by SAD tend to feel happier. Whether you opt for an hour's walk in daylight, a winter holiday, or a full-spectrum lamp, you'll feel differently with lots of light.
